The documentary highlights public sculptures similar to Dream the artist has created across the globe, providing a chance to see its equivalents in Spain, France, Japan, England, Korea, Germany, Canada and America.

Jaume Plensa explained in the film: “It’s a portrait of a girl dreaming. One of the ex-miners I worked with told me, ‘when you are 300m down in the pit, the darkness is so deep that light becomes a dream. I said ‘wow’ - I had never really thought about light, it changed my concept of light completely.”

Gary Conley, who led the ex-miners group behind the Dream project, told the interviewer: “We’ve had 400 years of mining here, so when the pits closed the whole area struggled and it was a bleak place.

“We entered an arts competition called the Big Art Project. At first Jaume unveiled his idea of a giant miner’s lamp. We had to go back and say he’d kept us in the past. Then he unveiled his original idea, Dream, which he’d scrapped as he thought we wouldn’t like it - but we thought, this is it!”